Looking to hire? Don’t ask for the impossible by Stephenie Overman @FortuneMagazine February 24, 2011, 3:41 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons With more job candidates out there, employers are getting picky, sending their recruiters out on endless (and fruitless) missions. Here are a few ways to get the best out of a recruiter.It’s a buyer’s market for companies looking to hire, but managers aren’t giving recruiters high marks for the candidates they are delivering.Only one in three managers who have hiring authority is satisfied with the influence recruiting has on their business, according to research and advisory firm Corporate Executive Board.It’s easy to blame recruiters, both in-house and external, says Todd Safferstone, managing director of Corporate Executive Board. Managers “think recruiting should be a cakewalk” because the market is teeming with candidates.“Haystacks are bigger, but the number of needles is largely unchanged. Hiring managers won’t be able to cut through those haystacks on their own,” Safferstone says.It is true that “active candidates are loving organizations to death right now. It’s spray and pray” when it comes to sending out resumes, he says. Corporate Executive Board reports that between 2007 and 2010 the average number of applicants increased by 128%.However, that surfeit can lure managers into demanding “purple unicorns,” candidates with qualifications that go far beyond what’s required, Safferstone says.Ed Davis, former head of staffing for United Airlines and ConAgra Foods CAG , is familiar with the problem. “In a market where there appears to be a surplus, the common mistake is to tack on too many unnecessary requirements.”If you’re planning to hire someone, you need to clearly identify the skills that are crucial for that position, Davis says. How will you define success in the job? What are the truly necessary leadership and technical skills?“When you layer those [extra] things on, it’s like looking for a needle in a haystack. It may take longer to get [the new employee] and is what you ultimately end up getting really what you need for on-the-job success?”Recruiters who just nod their heads and agree to hunt for purple unicorns aren’t doing you any favors, says Safferstone. And those “who want recruiters who are order takers are likely to get lower quality candidates … at greater expense.”Instead of a complacent order taker, you want to a recruiter who makes you a little uncomfortable, Safferstone says. “The best recruiters ask the most non-obvious questions: Do you need to hire someone? Tell me what the day-to-day experience is going to be.”John Vlastelica, managing director for Recruiting Toolbox, Inc., a Seattle-based consulting firm, believes that once you make a decision to hire someone, you should expect a good recruiter to set up a 30 to 60-minute strategy meeting “to discuss how to find, engage and sell candidates who fit the profile, identify quality (not just available!) interviewers who can help to assess and sell candidates, and discuss things like compensation, relocation assistance, immigration, and the overall process,” Vlastelica says in an email.The best recruiters might expect even more of your time, says Vlastelica. Although a great recruiter “can get an A-player on the hook,” you’re the one who will need to reel that candidate in. “A-players need to experience the investment a hiring manager makes in them as a candidate, as it tells them volumes about how good — or how bad — it may be to work for that same manager once hired.”If it’s so difficult to get what you need from recruiters, should you just do it yourself?No, it takes far too much time to locate good candidates and screen them when that’s not part of your day-to-day job, Davis says. Recruiters “know where the talent is. They know how to access talent in a way that’s efficient and legally compliant.”The best recruiters have deep knowledge on both the state of the demand for talent and the available talent, according to Safferstone. That knowledge allows a recruiter “to say that finding an accountant who speaks five languages is never going to happen at what you are willing to pay, with the quality you want, in the timeframe you want.”These recruiters “really know what they’re talking about. They’ve earned the right to challenge the hiring manager.”If a recruiter you work with hasn’t stepped up, spell things out, Safferstone says. It’s best to say “here’s exactly what I need [and] why I need it.”If you feel the recruiter can’t meet the challenge, you may need to raise the issue with the head of recruiting or human resources.But before you do that, Safferstone recommends talking with the person who is most in tune with the current recruiting situation. That person, perhaps a more senior manager or head of HR, “might be able to give you a reality check” on whether your expectations are reasonable.Be fair — make sure you haven’t been giving the recruiter a moving target. “A lot of recruiters report [that] managers have difficulty sticking to the original job description. They keep changing requirements, Safferstone says.”And when it comes time to decide, decide.“Dithering on the decision can be really dangerous,” Safferstone says.Managers who take their time shopping around should understand that the best candidates will slip away.“Every day you delay, the quality-of-hire ticks down. Most business managers recognize the point of diminishing returns, but they don’t tend to recognize that in hiring.”More from Fortune.com: 5 rules on cultivating power Lawyers: Say farewell to that guaranteed raise Giving the performance review an extreme makeover —-Coming soon: You Can’t Fire Everyone Have you been fired — or been the one swinging the axe? Tell us your stories. We’ll highlight the most interesting and instructional stories in a section debuting in March. Send an email to firstname.lastname@example.org.